Conventionally, in heavy duty tires which are mounted on vehicles like a truck or a bus mostly operating on straight routes, in order to prevent the uneven wear of a tread shoulder unit, specifically, a shoulder rib and the like which configure the rib of the tread shoulder unit, there is widely used a method to arrange an uneven wear absorbing rib (BCR) provided with a step in the circumferential groove so as to retain a lower position than the tread of the rib (for example, Patent Document 1).
According to such an uneven wear absorbing rib, in the region provided with the step, it is possible to generate the shear force in the reverse direction with respect to the forward direction of the vehicle. For this, the shear force of the forward direction with respect to an edge unit of the shoulder rib is reduced. Accordingly, the uneven wear of the shoulder rib can be prevented.